This Program Project application proposes a broad-based effort to extend the limits of behavioral methodology for teaching and evaluating people who have severe, lifelong learning difficulties. In particular, the research is aimed at those whose language skills render them difficult or impossible to teach with traditional methods of instruction. The primary study population will be institutionalized mentally retarded children and adults whose future is likely to include community placement. The methodology will also be examined in smaller-scale studies of higher-and lower-functioning individuals -- those with specific learning disabilities and profound mental retardation, respectively. The studies will focus on a number of advanced conditioning techniques that can establish new stimulus-stimulus fading, and delayed prompting; (b) simple-and conditional-discrimination procedures that produce functional and/or stimulus equivalence; (c) constructed-response matching to sample; (d) stimulus component prompting; and (e) prompting procedures that make use of specific and generalized controlling relations. Previous studies have shown that these techniques have significant potential not only for studying learning but also for providing remedial training in regular and special education settings. Studies have shown further that these techniques can potentially increase teaching efficiency because they lead to the emergence of new behavior that has not been directly conditioned. Yet to be accomplished, however, is the next logical step--integrating the techniques into a comprehensive methodology for establishing and studying substantial repertoires of stable, flexible, adaptive behavior. The seven projects proposed here will approach this objective by developing methodology for teaching a variety of preacademic performances, including those involved in rudimentary reading and mathematics. The primary research focus is on fundamental behavioral processes that are likely prerequisites for such performances. The research will also attempt to determine relationships between subject variables (e.g., functional level) and the efficacy of different instructional procedures.